Fox entertainment chairman Kevin Reilly says “24” will be back for a 12-hour limited run and that the remaining “American Idol” judges are welcome to return next season. He also said the show would “likely” go back to having three judges.

Reilly said he could not confirm a report by TheWrap last week that all four current “American Idol” judges will not be back.

“No,” he said, “it’s confirmed that one judge is not coming back.”

He was referring to Randy Jackson’s announcement last week that he will exit the show.

Asked if the other judges would be welcome back, he responded, “Welcome back, absolutely.” And he said the show would likely go back to three judges, the number it had when the show began.

He also detailed plans for what could be the first of several “24” comebacks. Reilly spoke to reporters in a conference call prior to Fox’s upfront presentation to advertisers Monday.

Though the original conceit of “24” was that it ran in real time across 24 hours, the new “24” will unfold over just 12 hours, and will likely begin airing in May. Reilly said it will feature only the most eventful hours in a new Jack Bauer adventure.

He also said the Kiefer Sutherland series could return for more than one additional run.

He also said a “who’s who of Hollywood” has expressed interest in taking part in the show, and that its producers began to realize that a limited-run series was the best way to continue the show as plans for a feature film fell apart. One reason the show remains popular, Reilly said, is that it was “creatively vibrant” when it ended.

He also said the network doesn’t have “any new judges to talk about” on “X Factor” yet, but will make announcements soon.

Reilly’s network is making several unconventional moves next season as it deals with changing viewing habits and lower ratings. It is coming off a 2012-13 season in which “American Idol” ratings slipped and Fox lost first place in the key 18-49 demographic to CBS.

Among its plans are to begin airing shows at different times throughout the year, instead of just at the start of fall and midseason. Next season, for example, Fox will begin airing the new J.J. Abrams drama “Almost Human” late in the fall. And the new “Gang Related” will begin airing in May and run into the summer.

“I’d like to strike the phrase midseason from our lexicon, frankly,” Reilly said.

The network will also continue to do shorter episode orders than the traditional 22 or 24 episodes, continuing a habit it started last season when it ordered just 15 episodes of “The Following.”